The Predominance of Giardia duodenalis AII sub-assemblage in young children from Salvador, Bahia, Brazil

Abstract

Introduction. Giardia duodenalis is an intestinal protozoan with a high prevalence in children of developing countries. Molecular studies revealed a great genetic diversity of G. duodenalis, with assemblages A and B found mainly in humans. Despite its importance, the information on the molecular epidemiology of human giardiasis is still limited in Brazil.Objective. To characterize G. duodenalis molecular isolates in children from Salvador, Bahia, Brazil.Materials and methods. Giardia duodenalis positive fecal samples were obtained from 71 children from two day care centers and 39 users of a clinical analysis laboratory. Samples were analyzed by PCR-RFLP of the glutamate dehydrogenase (gdh) and beta-giardin genes and by the sequencing of beta-giardin.Results. Of the 110 G. duodenalis samples, 80 (72.7%) amplified one or both target genes. Of these, 62 (77.5 %) were identified as assemblage A and 18 (22.5%) as assemblage B. The subassemblage AII was identified in 58.8% (n=47) of isolates followed by the sub-assemblage AI (18.8%, n=15), BIV (11.2%, n=9), and BIII (5.0%, n=4). The AII sub-assemblage was the most frequent in children of both day care centers whereas AI was found only in the group attended at the clinical laboratory. Sub-assemblage AII predominated in children under two years.Conclusions. The higher frequency of AII sub-assemblage suggests that anthroponotic transmission is more common in Salvador, but that zoonotic transmission pathways are also present and a change in susceptibility to different molecular patterns of Giardia may occur during child growth.

Molecular Genotyping of Giardia duodenalis in Humans in the Yazd County, Central of Iran

“…In this study, assemblage B was more prevalent than assemblage A. The discovery was comparable to the results of research conducted in Malaysia ( 19 ), India ( 20 ), Australia ( 21 ), UK ( 22 ), Bangladesh ( 23 ), as well as studies conducted in the southern ( 15 ) and northwestern regions ( 24 ) of Iran. However, the findings of studies undertaken in Shushtar ( 25 ), Andimeshk ( 14 ), and Shiraz ( 26 ) in Iran, as well as Brazil ( 17 ) and Egypt ( 27 ), do not support this conclusion.…”

High Diversity of Giardia duodenalis Assemblages and Sub-Assemblages in Asymptomatic School Children in Ibadan, Nigeria

“…However, it should be noted that both assemblages A and B have zoonotic potential [ 68 ], so we cannot rule out the possibility that an unknown fraction of the G. duodenalis infections detected here were indeed of non-human origin. Additionally, previous molecular-based epidemiological studies conducted in Brazil and Syria have evidenced that sub-assemblage AII was more prevalently found in young children than in individuals of older ages [ 69 , 70 ]. In the present study, AII results were found in 20% (12/60) of the participating children.…”

Giardiasis in children and dogs, and the first report of assemblage E in dogs from northeastern Brazil

“…We observed the presence of diarrhea in the infection with both assemblages. In contrast, Figueiredo Pacheco et al (2020) detected cases of diarrhea only in children infected with the AI sub-assemblage. They also found that 91.8% of children with giardiasis had no diarrhea or any other relevant symptoms.…”

“…Assemblages A, B, and E were identified in children and assemblage E in dogs (Table 2). Regarding bg sequences, three of them were identical to sequences obtained from cattle (KY769092, MH079430) and sheep (KY633473, MK573342) identified as assemblage E. One bg sequence, identified as assemblage A, was identical to sequences obtained from children (MG845549, MG845542) in Salvador, Brazil (Figueiredo Pacheco et al, 2020). All tpi sequences identified as assemblage A were identical to sequences obtained from humans (MH673818).…”

“…Assemblages A, B, and E circulate among Brazilian children, with a higher occurrence of assemblage A. The majority of infected children are reported from daycare centers in urban and peripheral areas (Kohli et al, 2008;David et al, 2015;Quadros et al, 2016;Scalia et al, 2016;Figueiredo Pacheco et al, 2020). Brazilian dogs are infected with assemblages A, B, C, D, and E, among which assemblage A predominates (Fantinatti et al, 2020).…”